The present invention relates to medical imaging of the prostate, and more particularly, to automatic segmentation of the prostate in magnetic resonance images.
Detection and delineation of the prostate in medical image data is an important problem in medical imaging analysis. For example, prostate cancer is often treated by radiation therapy where precise targeting of the prostate is important. The improved contrast of magnetic resonance (MR) abdominal image over other imaging modalities affords more accurate and consistent manual contouring of the prostate. Consequently, MR imaging now plays an increasing role in prostate radiotherapy planning. Accordingly, automated methods for segmenting abdominal structures in MR are desirable to improve the clinical workflow. However, automated segmentation of the prostate in MR images is challenging due to global inter-scan variability and intra-scan intensity variation caused by an endorectal coil, as well as due to the similar appearance of the prostate and the seminal vesicles at the apex, geometric variability due to disease, and adjacent structures such as the rectum and the bladder.
Conventional approaches for automatic prostate segmentation are typically registration-based. That is, one or more template images with segmentations are registered to the target image and the aligned segmentations are fused. Variation in intensity and appearance are typically overcome through the use of appropriate energy (e.g., mutual information) and the use of multiple templates. Although such registrations methods perform well when one of the templates is similar to the target image, they are often computationally expensive, typically requiring several minutes to return a segmentation.